Tape feed alarm



Nov 5,1946. M. PQTTS TAPE FEED ALARM Filed May 22, 1942 I NVENTOR. LOUIS M. POTTS Patented Nov. 5, 1946 TAPE FEED ALARM Louis M. Potts, Evanston, 111., assignor to Teletype Corporation, Chicago, 111.,

Delaware a corporation of Application May 22, 1942, Serial No. 444,067

This invention relates to telegraph transmittingapparatus and particularly to a strip feed alarm device for indicating the manifestation of defective strip feeding conditions. V

In the telegraph communication field, tape is employed as a medium for carrying indicia of telegraph signal code combinations, usually in the form of permutably arranged perforations. Ordinarily, the tape is first perforated either by means of key operated perforator or by means of a signal controlled reperforator and later used in connection with a tape transmitter to send si nals in code combination form overv an outgoing line. The tape, in performing its operating functions, is subject to stresses and strainswhich may at times cause the tearing of the feed holesand possibly a complete rupture of the tape. 'Itvis apparent that any such undesirable conditions may seriously impair transmission of messages and cause distortion or loss of signals, particularly so if such conditions were not immediately rectified. The use of tape-operated transmitters which are unattended by an operator is growing constantly and consequently the desirability of the arrangement as herein provided is enhanced inasmuch as the problem of defective tape feeding conditions is obviously not as serious when a transmitter is under the constant surveillance of an operator.

It is therefore the prime object of this invention to provide a mechanically controlled strip feed alarm which immediately brings to an operator's attention the manifestation of adefective tape feeding condition. 7

Other objects, features and advantages of the present invention will become evident as the invention is further described in detail.

By the present invention there is provided a.

mechanically controlled alarm device in which two contact operating levers are normally main- 13 Claims." (oi. 177 311 tained in'inoperative positions by a cam arrangement and wherein a relative displacement of the cams included in the arrangement when defective tape feeding conditions occur, causes one or the other of the levers to operate both an audible and a visible signaling means. The use of both audible and visible signal indicating means in the present invention is particularly desirable in view of the fact that the apparatus heren disclosed is designed especially for usein installations which may include a large number of transmitters.

It is therefore necessary to bring to the operators attention not only an indication of the occurrence of a defective feeding condition by an audible signal but also by a visible signal as well in 2 order that the operator may know in which particular one of the. transmitters the condition exists. The invention will be more readily understood by reference to the following detailed description and the drawing wherein,

Fig. 1 is a perspective view of oneembodiment of the present invention partly in section: and with certain portions of the apparatus omitted for the sake of clarity; j q 7 Fig. 2 is a plan View of the embodiment of the invention disclosed in Fig. 1;

Fig. 3 is a schematic representation of thecams used in connection with'the invention disclo'sed in.Fi s. nd Fig. 4 is a plan view partly in section of asecond embodiment of the present invention;

Fig. 5 is a side view partly in section of the apparatus disclosed in Fig. 4; and

Fig. 6 is a perspectivejview of the cam control means employed in theembodiment of theinvention disclosed in Figs.3 and l. f g Referring now 'to the drawing, the first embodiment of the invention which is disclosed in Figs. 1, 2, and 3 will now be described'in detail. The present invention-may be conveniently incorporated for use withtape transmitters such as disclosed in the patent to Goetz', PatentNo. 2,296,845 issued September 29,

1942, and in order to facilitate the description of the present application'it willbe presumed that the ratchet wheel 56 disclosed therein the'shaft 58 which carries the ratchet 56, and the sprocket wheel 59 are the same as the similarly numbered elements appearing in the present disclosure. As described in detail in the just referred to patent, the tape is intermittently fed forward as the ratchet 56 is periodically advanced by mang r a pawl associated with'a steppingifiagnet which thereby causes'the rotation of the shaft'58faifd the tape feed sprocket 59. In, the present revels,

ti'on' there is attached to the shaft 58 by means are similar in configuration to the cams 62 and 53 Which were previously described.

Carried at the end of the sleeve 61 opposite 1 Referring now again to the shaft 58 (Fig. 2) it can be seen that there is carried thereon for rotation therewith a gear H which drives an idler gear 12 which in turn drives a gear 64 which is fixedly attached to the shaft 65. It is therefore apparent at this point that as the sprocket feed wheel 59 intermittently advances the tape H forward, the pull of the tape enables the second sprocket wheel 65 to be also intermittently advanced inasmuch as the feed holes of the tape are positioned on the pin projections of both sprockets. It is therefore further observable that inasmuch as sleeve 61 is attached to sprocket 65,

as sprocket 65 is advanced, the sleeve 6 will also distances during normal operation of the appaa n c Mounted in alignment with cam 63 associated with' s'haft 58 and cam 69 associated with shaft 66 in a contact operating lever 13 which has an upstanding arm 14 adapted to cooperate with the cam 69 and a second upstanding arm 15 adapted to cooperate withthe cam 63. A horizontally extending arm 16 of the lever 13 is in engagement with an insulating portion 11 of a contact spring 18 which is normally spring urged away from its associated spring contact member 19 The lever 13 'is normally urged to rotate in a counterclockwise direction about pivot shaft 82 as viewed in Fig 1 under the influenc'eofspring 8| so that the upstanding projection 15 and the upstanding projection 14 are urged into engagement with their associated cams. Also mounted upon the shaft 62 is a second lever 83 which is exactly the samein construction as the just described lever 19. Upstanding portion 84 of lever 83 is adapted-to cooperate with cam 68 while the upstanding arm 85 of lever 83 is adapted to cooperate with the cam 62 and the horizontallyextending arm 86 is adapted to cooperate with the insulating port'ion 'l 'l of contact spring I8 in a similar manner to the horizontally extending arm 16 of lever i 3 and likewise a spring 81 normally urges lever- 83 in a counterclockwisedirection as viewed in Fig. -1. The contact spring '!8- is therefore common to and operable by either lever 13 or I I fheraisedportions qf-cams 62 and 63 will be slightlyin excess of 90 degrees of their respective peripheralcontours (Fig. 3) while the recessed portions of the cams will be slightly less than 90 degrees of their respective peripheral contours and the camsfl and 63'will be so positioned with relation to each otherthat the high portions of one cam will be opposite the low portion of the other camas shown in Fig. 1, for apurpose which will hereafter appear. The high portions of cams 69 and 69 willconsist of segments of slightly lessthan 90 degrees ofthe peripheral contour of the cams-While the recessed portions of these cams will be slightly in excess (Bf-'90 degrees of theperipheral contour of the camsand the raised portions of cam I58 will be positioned adjacent the recessed portions of cam 59 as clearly shown 'inFig. 1.

It can now be seen by referring to Fig. 1 that as long as the tape H0 is being fed forwardly by sprocket 59 and the sprocket 65 is being rotated through the intermittent pull of the tape H0, the levers l3 and 83 will be retained in a clockwise position. This is due to the fact (referring first to lever 73) that cams 62 and 63 when in phase relationship with camsl68 and 69 are so arranged that the high portions of the cams work alternately against the upstanding arms 15 and 14. Cams 63 and 69 are normally so positioned that when the end of arm 15 has been traversed by a high portion of the cam 63 the other arm 14 will have already been engaged by the" high portion of cam 69. Lever 94 is controlled in a similar manner by its associated cams and-it is therefore apparent that as long as operating conditions are normal, neither one of the levers 13 or 83 will be allowed to pivot and close the contacts 9| to cause operation of an alarm device to be hereafter described. Should a breakage of tape occur, shaft 58 will continue to rotate and drive the cams 62 and 63 while the sprocket 65 will no longer rotate inasmuchas the tape no longer exerts a pull thereon,'and therefore cams 68 and 69 come to a stop. At'this time either one or the other of the arms 14 of lever 73 or the arm 84 of the lever 83 rests on a high portion of the cam while the other arm is positioned over a low portion of the cam. Therefore, if for instance arm 74 of lever 13 were over a low portion of cam 69 when shaft 66' came to a halt then when cam 63 is in a position whereat the arm 15 may ongage a recessed portion of its cam, the lever 13 would be able to pivot to a position under the influence of spring 8| to close the contacts SI and operate the alarm device. Of coursea similar condition would occur if the arm 84 of lever 83 came to a position overlying a recessed portion of cam 68 when the shaft 66 came to a stop.

The pair of earns 68 and 69 are provided with raised portions slightly less than degrees and with recessed portions slightly more than 90 degrees with the high portions of one cam adjacent the low portions of the other cam. This enables an overlapping cooperation of the high portions of cams 68 and 69 with the high portions of cams 62 and 53, respectively, which, as already mentioned, are slightly in excess of 90 degrees to normally hold levers 13 and 83 in their respective inoperative positions when operat'ing in proper phase relationship. Due to the fact that cams 68 and 69 are staggered with respect to each other, that is, with the slightly under 90 degree high portions of one cam adjacent the slightly more than 90 degree low portions of the other cam, it is always assured that the cam engaging portion of one ofthe levers I3, 83 will overliea low portion of one of the cams 68, 69 when they cease to rotate as explained, andis thus enabled to pivot-and operate the alarm device irrespective of the stop positions of cams 68 and 69.

The closing of the contact pair 9! completes thealarm circuit over conductors 92 and 93 so that an audible signal 94 and the visible signal 95 are placed into operation and will be periodically operated thereafter as the shaft 58 continues to rotate to cause a periodic movement or the particular lever whose upstanding arm M or 8 2' was opposite a low portion of the cam when the shaft 66 came to a stop. The attendant at this time will thus be informed that a defective tape feeding condition has occurred and will then immediately be able to rectify the 'cond i on,

In order to reset the cams 68 and 69 into phase relationship with the cams 62 and 63, a special reset mechanism is provided which will nowbe described. In tape transmitters such as disclosed in the Goetz-patent, already referred to;

there is provided a bar I08 which is similar to the bar I08 disclosed in Figs. 1 and 2 and which is employed at the start of transmission tocondition the apparatus for operation. Adjacent to the bar I08 is suitably mounted a bracket I09 which carries a U-shaped lever III which is pivoted at H2 and carries an extending'arm H3. Lever III is normally urged in a counterclockwise direction by spring I as viewed in Fig. 2., The upper and lower arms H8 of the U-shaped member terminate in a rounded portion I I5 which rides in a groove of a collar member H6 which is suitably keyed to a slot H1 in shaft 66 and rotatable therewith. The collar,

member I I6 includes a pair of disc like side members I2I and I22. The disc member I22 has struck up therefrom an upstanding projection- I23 adapted to cooperate with two pins I24 and I25 carried by sprocket 65 in a manner to be immediately hereafter described.

The U-shaped member III which is mounted upon bracket I69 is during normal transmission restrained from movement by the abutment of projection H3 with an extending portion H4 of the bar I06. However, when it is desired to start transmission or to reset the tape sprockets into phased relationship, the bar I08 is depressed and the projecting portion H4 of the bar is removed from the path of the projection H3 so that the U-shaped member III is then free to move in a counterclockwise direction as viewed in Fig. 2.

under the influence of spring I20. This causes the upper and lower arms H8 of the U-shaped' member III to shift the collar member II 6 axially upon the shaft 66 along the keyway II1 to its phasing position.

When inserting a new or an unused portion of a broken tape, the operator depresses the bar I08 with one hand and with theother hand posi.--

tions the tape upon the sprocket 65 and there-,- after with the same hand rotates the sprocket 65 manually until sufficient tape has been fed out for engagement with the main feeding sprocket 59. The sprockets 65 and 59 will be so placed with respect to each other that by the time. the tape has been positioned .upon the. front sprocket one or the other of the pins I24 of.

I25 will have come into engagement with the upstanding projection I23 of disc member I 22 of collar member H6 which is carried by the shaft 66 and therefore the sprocket will again be returned to a phase relationship. This occurs when the collar member II6 assumes its phasing position as described above. Due to the fact that the collar H6 is rotatable with the shaft 66, as the sprocket 65 is rotated manually by the operator, a point will be reached as ex .v

plained wherein the pins I25 or' I24 will engage with the projection I23 so that the sprocket 65 and the collar I I6 will thereafter rotate as a unit and thereby the gear members 64, 1 I, and 12 will now be described. This second embodimentof the invention may also be readily incorporated into the previously referred to transmitter disclosed in the Goetz patent. It will be presumed that ratchet wheel I56 is equivalent to the ratchet wheel 56 shown in Figs. '1 and 2 and likewise the shaft I58 and feed sprocket I59 are equivalent to shaft 58 and the feed sprocket 59, respectively, as disclosed also in Fig. 1. It had been previously mentioned that the parts 56, 58, and 59 of Figs. 1 and 2 were numbered similarly to the like parts appearing in the Goetz patent. Shaft I58 will be suitably journaled in the frame and will be intermittently advanced by the engagement of a stepping pawl with the ratchet I56 as is well known in the art. The tape I6! will be threaded over the teeth of the feed sprocket I59 and will he therefore intermittently advanced as the ratchet I56 is actuated. Carried at the end of the shaft I58 opposite to the ratchet I56 is a gear I62 which drives a suitably mounted idler. gear I63 which in turn causes the rotation of a driving gear I64. In mesh with the driving gear I64 is a second idler gear I65 which drives the gear I66. Integrally formed with the gear member I64 is a sleeve I61 which carries a cam member I66 having a peripheral contour in which the raised portion of the cam is slightly in excess of 180 degrees. The sleeve I61 is attached to the shaft I69 by means of a set screw HI and it is thus obvious that the shaft I69'is rotatable with the gear I64.

Also mounted upon the shaft I69 and freely rotatable thereon is a second feeding sprocket I12 which is directly in alignment with the first feeding sprocket I59. It is therefore observable that as the tape I 6| is advanced by the first feeding sprocket. I59 inasmuch as the tape by means of its feed holes engages the teeth of the'second feeding sprocket I12, the second feeding sprocket I12 will be rotated about'the shaft I69 by the pull of the tape. The feed sprocket I12 has integrally formed therewith a sleeve I13 which surrounds the shaft I69 and carries a cam member I14 which has a peripheral contour in which the raised portion of the cam is slightly less than 180 degrees for a purpose which will hereinafter appear.

When the tape is' properly advanced by the feeding mehanism, the cams I14 and I68 will be so arranged that their high portions together present a 360 degree closed surface to the cam engaging portions I16 of a pair of levers I11 and I18 which are pivoted at I19 and I 8 I, respectively, and the came engaging portions I16 of which are 180 degrees apart and normally urged towards each other by means of resilient spring members I associated with contacts I83 and I64. The lower end portions of the levers I11 and I19 terminate in curved contact engaging portions H9. These contact engaging portions II9 are adaptable to cooperate with contact members I83 and I84 which control the alarm circuit. Normally the contact engaging portions II9 of the levers rest against the insulating members I85 associated with the resilient spring members I80 of the contacts and hold the spring members in flexed condition to thus urge the levers I11 and I18 to pivot towards each other. should a defective or irregular tape feeding condition occur one or the other of the levers will be pivoted under the influence of the spring contact members I89 as will later appear and will close one or the other of the contact members I83, I84; The 'closure of either of the contacts However,

to become effective to operate an audible alarm device I88 and the other to operate a signal lamp I89 which will announce to the operator the occurrence of a defective tape feeding condition.

The operation of'the contact control levers I'lland II8'will now be described in more detail. it

will be presumed that the tape stepping sprocket- I59 is in normal operation and is intermittently advancing the tape I6 I. If a breakage of thetape should now occur, the main tape feed sprocket I59 will continue to operate. However, due to the fact that the second tape feed sprocket'l I2 is operated by the pull of the tape it will come to rest. Therefore, inasmuch as the cam I14 is carried by the sleeve I73 which is connected to the feed sprocket I12, this cam will likewise come to rest. n the other hand, the cam I68 will continue to rotate by means of the drive aiforded by the'gear s I62, I63, and I64. In view of the fact that the high portion of the cam H4 is slightly less than180 degrees and the cam engaging portionsIlS of the levers IT! and I78 are 180 degrees apart, one of the levers will be held in its outer positionby engagement with the high portion of cam I'M.

When the cam comes to rest, While the other lever will be opposite the low portion of the cam and when the cam I68 is in a position to also present its low portion to this last mentioned lever, the lever will be permitted to carry itscam engaging portion H6 inwardly under the influence of its associated spring contact member 586, enabling its contact engaging portion H9 to operate its associated contact member I83. The alarm device will then thereafter be intermittently operated" as the cam I68 continues to rotate and present its low portion to the lever whose cam engaging portion I76 happens to' be opposite the low portion of the cam I16. This condition will continue until the operator has made the necessarycorrections in the apparatus. 7

'It'will be understood that a similar resetting mechanism which was described in connection with Figs. 1 and 2 could be readily incorporated into the embodiment of the invention disclosed in Figs. 4, 5, and 6 by mounting a collar member such as II6 disclosed in Fig. 2 upon the shaft I69 and providing the other necessary equipment which has already been described.

The purpose of providing the additional idler gtar I65 and the additional driven gear' I66 inmesh therewith is to enable the rotation of a suitably journaled shaft 192' which carries a third feeding sprocket I93. As shown in the drawing, the thirdfeeding sprocket'l63 is in direct align ment with the feeding sprockets I59 and I12 but is in a slightly elevated position with respect thereto.

enable a considerable portion of the tape to move over' the periphery of the feed sprocket R93 to thereby enable a better distribution of strain upon thetape. A strain relieving sprocket is particularly desirable in cases where the tape may be fed from arelatively large supply reel and in cases wherein it makes for better operation of the tape transmitter to remove the strain from'the tape prior to the movement of the tape into the transmitter proper where it performs its transmitting operations. One particular advantage of this is that it enables the centralization of the feed holes of the tape upon the teeth-=of the tape transmitters. If a strain were placed upon the tape at the main feeding sprocket, the feed.

The purpose of this arrangement is tov 8 holes would not be centralized with respect to the teeth of the sprocket but would be pulled to one side by the teeth of 'thesprocket. This would cause a slight misalignment of the signal perforations with the tape feelers and might impair the efliciency of signal transmission.

It will be understood that various changes and modifications may be made in the above-described specification without departing from the spirit and scope thereof.

What is claimed is:

1. In a tape feed alarm, feeding means for advancing a strip, a cam mechanism, means for operating said cam mechanism under the joint control of said strip and said feeding means, an alarm device, a pair of levers controlled by said cam mechanism for operating said alarm device, andmeans included in said cam mechanism for enabling the operation of one of said levers upon the failure of said strip to exercise control of said cam mechanism to thereby enable actuation of said alarm device which of said levers being actuatable depending on the phase positioning of said cam mechanism.

2. In a strip feed alarm, feeding means for advancing a strip, a first pair of movable cam members, means for moving said first pair of cam members in synchronism with the movement of the strip feeding means, a second pair of movable cam members, means for moving said second pair of cam members in synchronism with the movement of said strip to maintain a phase relationship with said first pair of cam members, and an alarm device controlled by said pairs of cam members, whereby said alarm device is operated by said pairs of cam members when said strip fails to maintain said phase relationship 'between said pairs of cam members.

3. In a strip feed alarm, feeding means for advancing a strip, a first pair of movable cams, means for moving said first pair of cams in synchronism with the movement of the strip feeding means, a second pair of movable cams, means for moving said second pair of cams in phase with saidfirst pair of cams and in synchronism with the'movement of said strip, a pair of levers each controlled by a cam of each pair of cams, and an alarm device operable by either of said levers, whereby one or the other of said levers is actuatable to operate said alarm device when said pairs of cams are not maintained in phase by said strip; which of said levers being actuatable depending on the phase positioning of said earns.

'41 In -'a strip feed alarm, feeding means for advancing a strip, a first pair of movable cams, a second pair of movable cams, said first pair of cams moving in synchronism with the movement of the strip feedingmeans and said second pair ofscamsmoving in phase with said first pair of cams and in synchronism' with the movement of said strip, an alarm device, and a pair of levers to control said alarm device, each of said levers being alternately controlledby a single cam of each pair of cams, whereby one or the other of said levers is actuatable to operate said alarm device. upon the failure ofisaid strip to maintain said phase'condition of said cams, which of said levers "being actuatable depending on the phase positioning of said cams.

.5. In a strip feed alarm, feeding means for advancing a strip, a first movable cam, means for moving said first cam in synchronism with the movement of the strip feeding means, a raised portion on said cm, a second movable cam,

1 means for movingsaid second cam in phase with.

the first cam and in synchronism with the movement of said strip, a raised portion on said second cam, an alarm device, and a pair of levers each having a portion engaging with said cams, whereby said raised portions of said cams are normally positioned with respect to each other to present a closed peripheral surface to said cam engaging portions of said levers while said phase condition is maintained to normally prevent operation of said levers, whereby one or the other of said levers is operative to control said alarm device upon the failure of said strip to maintain said closed peripheral surface of said cams under said phase conditions, which of said levers being actuatable depending on the phase positioning of said cams.

6. In a tape feed alarm, feeding means for advancin a tape, a shaft for driving said feeding means, a cam member carried by said shaft, a second shaft, a second cam member carried by said second shaft moving in sync'hronism with said tape to maintain a phase relationship with said first cam member, and an alarm device controlled by said cam members, whereby said alarm device is operable under the control of said cam members upon the failure of the maintenance of said phase relationship between said cam mem' bers.

7. In a strip feed alarm, feeding means for advancing a strip,. a shaft, a pair of movable cams carried by said shaft and operated by said feeding means, a second shaft, a second pair of movable cams carried by said second shaft and moved in phase with said first pair of cams in synchronism with the movement of said strip, a 1

pair of levers each controlled by a cam of each pair of cams, and an alarm device operable by either of said levers, whereby one or the other of said levers is actuatable to operate said alarm device when said pairs of cams are not maintained in phase by said strip, which of said levers being actuatable depending on the phase position of said cams.

8. In a tape feed alarm, feeding means for advancing a tape, first movable cam means,

means for moving said first cam means in synchronism with the movement of said tape feeding means, a second movable cam means, means for moving said second cam means in synchro nism with the movement of said tape to maintain a predetermined relationship with said first cam means, an alarm device including electrical contact means, and a pair of levers each engaging both of said cam means whereby when said phase relationship fails between said first and second cam means one of said levers closes said electrical contact means to cause said alarm device to operate, which of said levers being actuatable depending on the phase positioning of said cam means.

9. In a tape feed alarm, feeding means for advancing a tape, a first movable cam means, means for moving said first cam means in synchronism with the movement of said feeding means, a second movable cam means, means for moving said second cam means in synchronism with the movement of said tape to maintain a predetermined phase relationship with said first cam means, an alarm device including electrical contact means, and a pair of levers jointly controlled by both of said cam means, whereby when said phase relationship fails between said cam means one of said levers closes said electrical contact means to cause said alarm device to operate, which of said levers being actuable depending on the phase positioning of said cam means.

10. In a tape feed alarm, feed means for advancing a tape, a first movable cam means, means for moving said first cam means in synchronism with the movement of said tape feed means, a second movable cam means, means for moving said second cam means in synchronism with the movement of said tape and in phase with the operation of said first cam means, each said first and second cam means provided with complementally related peripheral contours, lever means in contact with both said cam means, and an alarm means controlled by said lever means which is ineffective when the complemental peripheries of said cam means are in phase and effective when the complemental peripheries of said cam means are out of phase.

11. In a tape feed alarm, feed means for advancing a tape, a first movable cam means, means for moving said first cam means in syn chronism with the movement of said tape feed means, a second movable cam means, means for moving said second cam means in synchronism with the movement of said tape and in phase with the operation of said first cam means, each said first and second cam means comprising a pair of cams, corresponding ones of which are provided with complementally related peripheral contours, and an alarm means ineffective when the complemental peripheries of said corresponding cams are in phase and effective when the complemental peripheries of said corresponding cams are out of phase.

12. In a tape feed alarm, feed means for advancing a tape, a first movable cam means, means for moving said first cam means in synchronism with the movement of said tape feed means, a second movable cam means, means for moving said second cam means in synchronism,

with the movement of said tape and in phase with the operation of said first cam means, each said first and second cam means provided with complementally related peripheral contours, a pair of levers each jointly controlled by said first and second cam means, and an alarm means operable by either of said levers, whereby one or the other of said levers is actuatable to operate said alarm means when the complemental peripheries of said cam means are out of phase, which of said levers being actuatable depending on the phase positioning of said cam means.

13. In a tape feed alarm, feed means for advancing a tape, a first movable cam means, means for movin said first cam means in synchronism with the movement of said tape feed means, a second movable cam means, means for moving said second cam means in synchronism with the movement of said tape and in phase with the operation of said first cam means, each said first and second cam means comprising a pair of cams, corresponding ones of which are provided with complementally related peripheral contours, a pair of levers each jointly controlled by one of said pair of cams of each of said first and second cam means, and an alarm means operable by either of said levers, whereby one or the other of said levers is actuatable to operate said alarm means when the complemental peripheries of said corresponding cams are out of phase, which of said levers being actuatable depending on the phase positioning of said cam means.

LOUIS M. POTTS. 

